Alternating-current-compensating system.



PATENTED SEPT. 15, 1903.

r L. A. HAWKINS. ALTERNATING CURRENT GOMPENSATING SYSTEM.

APPLICATION FILED FEB. 10. 1903.

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No. 738,799. YPATENTED SEPT. 15, 1903. L. A. HAWKINS. ALTERNATING CURRENT GOMPENSATING SYSTEM.

APPLIOATION FILED FEB. 10, 1903.

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No. 738,799 Iatented September 15, 190 3.

UNITED STATES PATENT OFFICE.

LAURENCE A. HAWKINS, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO STANLEY ELECTRIC MANUFACTURING COMPANY, OF PITTSFIELD, MAS- SACHUSETTS, A CORPORATION OF NEW JERSEY.

ALTERNATlNG-CURRENT-COM PENSATING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 738,799, dated September 15, 1903.

v Application filedIebruary 10,1903. Serial Nd.l42,783. (No model.)

To aZZ whom it may concern: The. operation is as follows: If the current Beitknownthatl, LAURENCEA. HAWKINS, in phase E F is in phase with its voltage,

a citizen of the United States, and a resident the current in coils J J will be ninety degree of Pittsfield, Massachusetts, have invented out of phase with the currentin coil K, since certain new and useful Improvements in Althe voltage in phase C D is ninety degree ternating-Current-Compensating Systems, of out of phase with the voltage in phase E F. which the following is a specification. There will then be no tendency for coil K The object of my invention is to provide to turn. It now the current in E F lags, means for compensating for the varying drop the ninety-degree relation between the cur- IO in voltage on alternating-current-transmisrents in coils J J and coil K will bedis- 6o sion lines due to varying loads and varying turbed and there will be a turning tendpower factors and for the drop in voltage in ency in coil K, which will be proportional to alternating-current generators due to lagging the amount of current in E F and to its lag. currents of varying power factors. As K turns, arm L cuts out resistance from :5 It is well known that the varying power the eXciter field-circuit, thus raising the eX- factors of lagging currents in alternating-can citer voltage, and consequently the generarent systems produce great variations of voltor voltage. 1f the current in E F increases tage by their demagnetizingefiect on the genin volume or lag, coil K will turn still farther erator and by the increased resistance-drop and raise the generator voltage still more.

20 on the line for a given amount of power be- It will be understood that it is not necescause of the low-power factor, and hence the sary that arm L itself should contact with regulation of thesysteln is seriouslyimpaired. the steps of rheostat M, as in some cases it In my present invention I remedy these evils may be preferable that the movement of arm by providing means for automatically raising L should merely work a relay, which in turn 25 the voltage to compensate for drop due to should move a contact over the steps of the varying currents and varying lag. rheostat.

Referring to the drawings, Figure l is a In order to permit of compensation for diagrammatic representation of a two-phase voltage-drop on non-inductive load, I prosystem embodying my invention. Fig. 2 vide the additional feature shown in Fig. 2,

30 shows a three-phase system embodying my together with certain modifications. In this invention. Fig. 3 shows a modification of figure I have shownathree-phase generator, my invention applied to a single-phase systhough it will be understood that the moditem, and Fig. at shows a further modification. fications shown are equally applicable to the Referring now to Fig. 1, A represents a two-phase generator of Fig. 1. In Fig. Zthe 35 two-phase generator. B is the generator-field. current for coils J J and coil K is obtained C D E F are the line-wires, C D belonging to through a series and a shunt transformer, one phase and E F to the other; G is an exrespectively, instead of directly, as in Fig. citer for the generator-field, and H is a hand- 1, and rheostat M is shown connected in the rheostat in the generator field-circuit. I is generator field-circuit instead of that of the 40 the compensator. It consists of the stationexciter. The addition that permits of comary coils J J in series with one-phase and the pensating for non-inductive loads is indimovable coil K in shunt to the other phase cated at O. of the generator. Coil K carries an arm L, O is an adjustable choke-coil or similar which as coil K revolves moves over the'conphase-shifting device in series with coils J J.

5 tacts of the variable rheostat M, which is 0011- The impedance of coil 0 is so adjusted that 5 nected in the field-circuit of exciter G. L is when the current in Eis in phase with its volheld normally againstthe stopVby weight W tage the current in coils J J lags behind the or by any equivalent device, such as a spring. current in coil K a little more than ninety N is a non-inductive resistance in series degrees. Under these conditions there will 50 with movable coil K. be some tendency for coil K to turn evenv on, roe

non-inductive load, and as this tendency is proportional to the current volume in E the voltage-drop due to line resistance will be compensated for. It now the current in E lags, the current in J J will lag still farther behind the current in K, the turning tendency of K will be increased, more resistance at M will be cut out, and the lag will be compensated for. Thus the voltage-drop for all lagging or non-inductive loads will be automatically compensated.

In the above applications of my invention 1 have made use of the phase difference produced by a multiphase generator; but my invention is equally applicable to a singlephase system. Such a system is shown in Fig. 3. Here, in addition to variable chokecoil 0 in circuit with coils JJ, I insert a condenser P in circuit with coil K. By this means I am enabled to obtain the same phase difference between J J and K as heretofore obtained from the multiphase systems. The other details are the same as heretofore described and need no further explanation.

The application of my invention is not limited to the generatingend of theline. It may also be applied at the receiving end to maintain the excitation ofa synchronous 1H0- tor or rotary converter at a proper value to compensate for lagging current in the mains. Neither is the application of my invention limited to affecting the field-current and the voltage of the generator. It may also be applied to cutting in or out turns in a regulating-transformer or similar apparatus. Fig. 4 shows one such arrangement. R represents a step-up transformer havingregulating-taps on its low-tension winding connected to contacts r 0*, which are adapted to be engaged by arm L. Arm L thus cuts outor in the regulating turns of the transformer R, and thus raises or lowers the voltage on the mains.

I do not desire to limit myself to the particular construction and arrangement of parts shown, since modifications therein which do not depart from the spirit of my invention will be obvious to those skilled in the art.

I claim as new and desire to secure by these Letters Patent 1. In a compensator for alternating-current systems, a stationary coil in a circuit in which the current varies in strength and phase with the current in the main circuit, a movable coil in a circuit in which the current bears a fixed phase relation to the potential of the main circuit, and means actuated by the movement of the movable coil for affecting the voltage in the main circuit.

2. In a compensator for alternating-current systems, a stationary coil in a circuit in which the current varies in strength and phase with the current in the main circuit, a movable coil in a circuit in which the current bears a fixed phase relation to the potential of the main circuit, means for maintaining a predetermined phase difference between the currents in the fixed and movable coils when the current in the main circuit is in phase with its voltage, and means actuated by the movement of the movable coil for affecting the voltage in the main circuit.

3. In an alternating-current system, the mains, a series transformer having its primary connected in one of the mains, a potential-transformer connected in shunt to the mains, a fixed coil connected to the secondary of the series transformer, a movable coil connected to the secondary of the potential transformer, and means actuated by the movement of the movable coil for affecting the voltage of the mains.

4. In an alternating-current system, the mains, a series transformer having its primary connected in one of the mains, a potenrial-transformer connected in shunt to the mains, a fixed coil connected to the secondary of the series transformer, a movable coil connected to the secondary of the potentialtransformer, a phaseshifting device for maintaining a predetermined phase difference between the currents in the fixed and movable coils when the current in the mains is in phase with the voltage on the mains, and means actuated by the movement of the movable coil for affecting the voltage of the mains.

5. In a compensator for alternating-current systems, a coil in a circuit in which the current varies instrength and phase with the current in the main circuit, a second coil in a circuit in which the current bears a fixed phase relation to the potential of the main circuit, one of said coils being movable, and means actuated by the movable coil for affecting the voltage in the main circuit.

6. In an alternating-current system, two coils, one of them being movable, in circuits in which the currents differ in phase by an amount varying with the lagin the main circuit, and means actuated by the movement of the movable coil for affecting the voltage of the main circuit.

'7. In an alternating-current system, two coils, one of them being movable, in circuits in which the currents differ in phase by an amount varying with the lagin the main circuit, means for maintaining a predetermined phase difference between the currents in said circuits when the lag in the main circuit is zero, and means actuated by the movement of the movable coil for affecting the voltage of the main circuit.

Signed at Pittsfield, Massachusetts, this 3d day of February, 1903.

RICHARD Evan, R. E. HAYNES. 

